In a manufacturing process of a semiconductor device, a semiconductor element after completion of bonding to a substrate is generally encapsulated with a molding resin such as a thermosetting resin in order to avoid contact with the outside. As the molding resin, for example, an epoxy resin having dispersed therein an inorganic filler including a silica powder as a main ingredient is used. For example, a transfer molding method including placing a semiconductor element bonded to a substrate in a molding mold, pressure-feeding a molding resin in the mold, thermally curing the molding resin, and molding the resin, is put into practical use as an encapsulation method using the molding resin.
Conventionally, a resin-encapsulated semiconductor device including a semiconductor element encapsulated with a molding resin is excellent in reliability, mass productivity, costs and the like, and is therefore in widespread use in conjunction with a ceramic-encapsulated semiconductor device using ceramic as a constituent material.
A semiconductor device of a one-side encapsulated structure such as a ball grid array (BGA) has the problem that stress is generated between an encapsulation layer including a cured resin and a substrate due to difference in shrinkage between the encapsulation layer and the substrate, and warpage is generated in a package by the stress. In order to suppress the warpage generation, investigation are made to increase a glass transition temperature of a cured resin as an encapsulation resin to thereby decrease the difference in shrinkage between the cured resin and a substrate (see Patent Document 1).
Patent Document 1: JP-A-10-112515